Layered LiNi_0.6Co_0.2Mn_0.2O₂ (NCM622) attracts widespread attention primarily due to its potential for high energy density and moderate thermal stability. However, the low initial coulombic efficiency (ICE) of the material limits the maximum utilization of their capacity. The capacity loss in the first cycle occurs under 4.0V and keep almost constant are considered as common characteristics for NCM-based materials. A clear cognition on the initial capacity loss may light the way to improve the practical reversible capacity of NCM622 at 4.0V. Conducting operando X-ray diffraction during galvanostatic charge/discharge cycling at different temperature (25°C, 45°C and 60°C) and different current (0.1C, 0.01C, 1C=120 mA g⁻¹) in the voltage range of 2.7–4.0V, we find that only 8% of the measured initial irreversible capacity loss is associated with parasitic reactions that form cathode/electrolyte interface, and that the dominant contributors include the slow Li⁺ diffusion kinetics (∼46% contribution) and irreversible O3/H1-3 phase transition (∼46% contribution). This semi-quantitative study provides new insight on initial capacity loss, guiding further targeted modification and fully utilization of NCM622.

层状LiNi _0.6 Co _0.2 Mn _0.2 O ₂ (NCM622)主要由于其具有高能量密度和中等热稳定性的潜力而受到广泛关注。然而，材料的低初始库伦效率 (ICE) 限制了其容量的最大利用。第一次循环中的容量损失发生在 4.0V 以下并保持几乎恒定被认为是 NCM 基材料的共同特征。对初始容量损失的清晰认识，可能为提高NCM622在4.0V时的实际可逆容量指明方向。在不同温度（25°C、45°C 和 60°C）和不同电流（0.1C、0.01C、1C=120 mA g ^{-1 ）的恒电流充电/放电循环期间进行原位 X 射线衍射}）在 2.7-4.0V 的电压范围内，我们发现只有 8% 的测量初始不可逆容量损失与形成阴极/电解质界面的寄生反应有关，主要贡献者包括缓慢的 Li ⁺扩散动力学（~ 46% 的贡献）和不可逆的 O3/H1-3 相变（~46% 的贡献）。这项半定量研究为初始容量损失提供了新的见解，指导进一步有针对性的修改和充分利用NCM622。